Byrd K.K.,Centers for Disease Control and Prevention |
Furtado M.,Engility Corporation |
Bush T.,Centers for Disease Control and Prevention |
Gardner L.,Centers for Disease Control and Prevention
AIDS Care - Psychological and Socio-Medical Aspects of AIDS/HIV | Year: 2015
We used the US-based MarketScan® Medicaid Multi-state Databases to determine the un-weighted proportion of publically insured persons with HIV that were retained, continued, and re-engaged in care. Persons were followed for up to 84 months. Cox proportional hazards models were conducted to determine factors associated with gaps in care. Of the 6463 HIV cases identified in 2006, 61% were retained during the first 24 months, and 53% continued in care through 78 months. Between 8% and 30% experienced a gap in care, and 59% of persons who experienced a gap in care later reengaged in care. Persons with one or more Charlson co-morbidities (HR 0.72, 95% CI 0.64-0.81), ages 40-59 (0.79, 0.71-0.88), mental illness diagnosis (0.79, 0.72-0.87), hepatitis C co-infection (0.83, 0.75- 0.93), and female sex (0.86, 0.78-0.94) were less likely to experience a gap in care. Between 27% and 38% of those not retained in care continued to receive HIV-related laboratory services. This Medicaid claims database combines features of both clinic visits-based and surveillance lab-based surrogate measures to give a more complete picture of engagement in care than single-facility-based studies. © 2015, Routledge. All rights reserved.
Stone C.P.,Computational Sciences, LLC |
Elton B.H.,Engility Corporation
Proceedings of WACCPD 2015: 2nd Workshop on Accelerator Programming Using Directives - Held in conjunction with SC 2015: The International Conference for High Performance Computing, Networking, Storage and Analysis | Year: 2015
The multi-zone scalar pentadiagonal (SP-MZ) benchmark, part of the multi-zone NAS Parallel Benchmark suite, is ported to graphics processing units (GPUS) using OpenACC compiler directives. The sequence of optimizations necessary to transform the SP-MZ algorithm from CPU-oriented to GPU-oriented is presented. The performance of the OpenACC implementation on GPUS is measured using predefined mesh sizes. We observe a 30% speed-up using the OpenACC implement on an NVIDIA Kepler K40 GPU compared to an eight-core Intel Xeon E5-2670 CPU with the small Class-A mesh (256 thousand points). Setting inter-zone boundary conditions directly on the device reduced run-time by 22% due to the high cost of host-device communication. Multi-device benchmarks with the larger Class-C mesh (4.3 million points) were scaled to 32 GPU n odes and matched or outperformed the CPU baseline with ten cores per node. Combining both CPU and GPU computing power improved the throughput on the Class-C mesh by 75%. We define a larger zone size with one million points per node to better reflect modern usage with codes similar to SP-MZ. The OpenACC GPU implementation outperformed the baseline multi-core CPU by 29% on this real-world mesh size. © 2015 ACM.
Gaquin K.G.,Engility Corporation |
Fields M.,U.S. Army
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016
Smartphones have put powerful sensor arrays in nearly everyone's pockets. Fusing the data from these sensors it is possible to estimate the phone's current orientation. In this study we utilize a 3 axis gimbal to compare the performance of multiple orientation estimation algorithms. Controlling the position of the gimbal allows us to compare the known device orientation to the estimated orientation. Using this same method we determine where each algorithm's faults lie, and where they begin to break down. Then repeating these movements we are able to compare each algorithm to each other. © 2016 SPIE.
Liu J.L.,Center for Bio Molecular Science and Engineering |
Dixit A.B.,University of Maryland, Baltimore |
Robertson K.L.,Engility Corporation |
Qiao E.,U.S. Navy |
Black L.W.,University of Maryland, Baltimore
Proceedings of the National Academy of Sciences of the United States of America | Year: 2014
Packaging specific exogenous active proteins and DNAs together within a single viral-nanocontainer is challenging. The bacteriophage T4 capsid (100 × 70 nm) is well suited for this purpose, because it can hold a single long DNA or multiple short pieces of DNA up to 170 kb packed together with more than 1,000 protein molecules. Any linear DNA can be packaged in vitro into purified procapsids. The capsid-targeting sequence (CTS) directs virtually any protein into the procapsid. Procapsids are assembled with specific CTS-directed exogenous proteins that are encapsidated before the DNA. The capsid also can display on its surface high-affinity eukaryotic cell-binding peptides or proteins that are in fusion with small outer capsid and head outer capsid surface-decoration proteins that can be added in vivo or in vitro. In this study, we demonstrate that the site-specific recombinase cyclic recombination (Cre) targeted into the procapsid is enzymatically active within the procapsid and recircularizes linear plasmid DNA containing two terminal loxP recognition sites when packaged in vitro. mCherry expression driven by a cytomegalovirus promoter in the capsid containing Cre-circularized DNA is enhanced over linear DNA, as shown in recipient eukaryotic cells. The efficient and specific packaging into capsids and the unpackaging of both DNA and protein with release of the enzymatically altered protein-DNA complexes from the nanoparticles into cells have potential in numerous downstream drug and gene therapeutic applications. © 2014 PNAS.
Carter J.,Indiana University – Purdue University Indianapolis |
Grommon E.,Indiana University – Purdue University Indianapolis |
Harris P.,Engility Corporation
Physical Communication | Year: 2016
Programming, management, and interoperability of land mobile radios within the public safety sector have long been salient issues for policymakers, practitioners, service vendors, and scholars. Despite receiving substantial attention in the form of government expenditure and agency task forces, there has only been moderate advancement in this concerning area. Recently, as part of a US Department of Justice-funded effort, an innovative technology known as wireless broadband over-the-air-programming (OTAP) has been translated from a conceptual model to an operational deployment. OTAP technology holds significant promise to enhance the management of public safety communications via land mobile radios. This research presents the concept of OTAP, the engineering behind the recently developed broadband enabled OTAP prototype, and conceptualizes how this technology can impact the processes used to facilitate public safety interoperability within the context of portable radio programming. © 2016 Elsevier B.V.
Weber B.V.,U.S. Navy |
Mosher D.,Engility Corporation |
Ottinger P.F.,Engility Corporation
IEEE Transactions on Plasma Science | Year: 2014
This technical note reviews solutions for planar, relativistic space-charge-limited (SCL) flow both for the single species case with electrons and for bipolar flow with electrons and protons. In most cases, numerical integration or evaluation of special functions is needed to obtain values for these solutions. Here, fit functions for these solutions are derived so that they can be used to calculate 1-D SCL electron and proton current densities and the bipolar enhancement factor for any voltage, including the range transitioning from nonrelativistic to relativistic behavior (approximately 0.1-2 MV, γ =1.2-5 for electrons and 102-105 MV, γ =1.1-100 for protons). These fit functions reproduce the exact values to within a few percent, or with an error correction, to within a fraction of 1%. These functions should be useful for evaluating SCL current densities for a range of problems where relativistic effects are important and the 1-D approximation is applicable. © 2014 IEEE.
Idris H.,Engility Corporation
15th AIAA Aviation Technology, Integration, and Operations Conference | Year: 2015
Choke points in the national airspace system are resources for which demand exceeds capacity and hence generate delays that propagate through the system network. Under nominal conditions, airports, and more specifically runways, are the main choke points that generate most delays. A historical data analysis is conducted in order to compare and rank the major airports of the national airspace system. A number of metrics and techniques are used in order to isolate locally generated delays, which demonstrate choke point effects, from delays that are propagated from other airports. Namely, throughput saturation is used to quantify how severely demand exceeds capacity, delay relative to unimpeded travel time is used to quantify queuing effects, and passing is used to isolate the local queuing delays from delays due to control activity to conform to downstream constraints. Results provide insights on how the major airports compare in terms of generating delay locally versus manifesting propagated delay. © 2015, American Institute of Aeronautics and Astronautics Inc.
Ahlstrom U.,Technical Center |
Jaggard E.,Engility Corporation
Transportation Research Part C: Emerging Technologies | Year: 2010
Adverse weather conditions are hazardous to flight and contribute to re-routes and delays. This has a negative impact on the National Airspace System (NAS) due to reduced capacity and increased cost. In today's air traffic control (ATC) system there is no automated weather information for air traffic management decision-support systems. There are also no automatic weather decision-support tools at the air traffic controller workstation. As a result, air traffic operators must integrate weather information and traffic information manually while making decisions. The vision in the Next Generation Air Transportation System (NextGen) includes new automation concepts with an integration of weather information and decision-making tools. Weather-sensitive traffic flow algorithms could automatically handle re-routes around weather affected areas; this would optimize the capacity during adverse conditions. In this paper, we outline a weather probe concept called automatic identification of risky weather objects in line of flight (AIRWOLF). The AIRWOLF operates in two steps: (a) derivation of polygons and weather objects from grid-based weather data and (b) subsequent identification of risky weather objects that conflict with an aircraft's line of flight. We discuss how the AIRWOLF concept could increase capacity and safety while reducing pilot and air traffic operator workload. This could translate to reduced weather-related delays and reduced operating costs in the future NAS.
Idris H.,Engility Corporation
27th Congress of the International Council of the Aeronautical Sciences 2010, ICAS 2010 | Year: 2010
The growth of air traffic demand is increasing the number of operations at major and secondary airports. As a result, the interdependencies between nearby airports are also increasing leading to the emergence of multi-airport systems (metroplexes). Often, these metroplexes constitute bottleneck capacities of the national air transportation network and hence a major cause of delay. The metroplex capacity limitations are caused by several inefficiencies. One such inefficiency is assigning the metroplex airspace among the competing airports based on procedures that segregate traffic by destination airport. These procedures limit the opportunity to share scare airspace resources dynamically between the airports and increase the mixing of slow and fast aircraft in single flows. This paper proposes assigning airspace and segregating traffic according to aircraft speed as opposed to the destination airport, resulting in sharing of airspace resources and potential throughput and flexibility gains. The proposed approach is analyzed, using simulation of hypothetical scenarios, in terms of airport throughput and aircraft trajectory flexibility.
Kuo V.H.,Engility Corporation
AIAA Guidance, Navigation, and Control Conference | Year: 2010
The non-cooperative aircraft increases the possibilities of midair collisions in the al-ready congested U.S. airspace. To counter this threat, a novel emergency evasive maneuver strategy is proposed, based on the reverse pure proportional navigation guidance, and requiring low levels of information concerning the non-cooperative aircraft. Using the time-varying nonlinear airborne equations of motion, a qualitative analysis of the relative trajectory between the own aircraft that performs the proposed emergency evasive maneuver and the non-cooperative aircraft that is assumed to collide with the own aircraft is presented. Sufficient conditions for the own aircraft to successfully avoid a collision with the non-cooperative aircraft are determined. Finally, simulation results are presented to demonstrate the effectiveness of the proposed emergency evasive maneuver against a pursing non-cooperative aircraft. Copyright © 2010 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.